Israel has announced its worst combat losses in more than a month after an ambush in the ruins of Gaza, and faces growing diplomatic isolation as civilian deaths mount and a humanitarian catastrophe worsens in the Palestinian territory.

According to Reuters, intense fighting was under way in both north and south Gaza, a day after the United Nations demanded an immediate humanitarian ceasefire. US President Joe Biden said Israel’s “indiscriminate” bombing of civilians was costing international support.

Israel reported 10 of its soldiers killed in the past 24 hours, including a full colonel commanding a forward base and a lieutenant-colonel commanding a regiment. It was the worst one-day loss since 15 soldiers were killed on Oct 31.

Most of the deaths came in the Shejaia district of Gaza City in the north, where troops were ambushed trying to rescue another group of soldiers who had attacked Hamas fighters in a building, the military said.

An Israeli military official said Israel had paid “a very heavy price” in the incident.